An ignition device having a laser is discussed in DE 199 11 737 or DE 101 45 944.
Spark plugs and operating methods of the kind cited above are used in particular in laser-based ignition systems of internal combustion engines. It is known to use the light guide device provided for supplying the spark plug with optical radiant power, such as pump light, to acquire optical operating data of a combustion chamber associated with the spark plug, or of the spark plug itself. In this context, optical operating data are correspondingly transferred from the combustion chamber via the light guide device to an evaluation apparatus, usually necessitating a separation of said optical data from the pump light.
In addition, the above-described known manner of ascertaining optical operating data from the spark plug or from a combustion chamber associated therewith is not usable with conventional spark plugs that have an integrated ignition laser.